U.S. Pat. No. 6,233,150 discloses a memory module having a memory card including a circuit board and a number of electronic components mounted on the circuit board. The memory module has, as a heat sink, a pair of covers arranged on mutually opposite surfaces of the circuit board and a pair of clamps that press the two covers onto the circuit board. In this case, each of the covers is thermally and electrically conductive and affords protection from electromagnetic radiation.
A complete heat sink of this type extends over all semiconductor devices of a memory module and thus thermally couples all of the semiconductor devices independently of their different power losses in a common housing. One disadvantage to this design is impermissible heating of adjacent semiconductor devices. A further disadvantage is the high material outlay, which thus increases the costs. Yet another disadvantage is that, in addition to producing the covers, it is also necessary to produce clamping elements in the form of clips, which increases the manufacturing costs.
U.S. Pat. No. 6,188,576 discloses a memory module having a housing cover in order to enclose a circuit board which has a plurality of individual semiconductor devices that dynamically generate a different quantity of heat. The housing cover provides a heat dissipation for the plurality of different memory chips. The different memory chips are thus thermally interconnected among one another via the circuit board and via corresponding solder balls. Besides the heat dissipation, the rigid housing protects both the circuit board and the chips.
In an embodiment disclosed in U.S. Pat. No. 6,188,576, a memory module includes a thermally conductive substance arranged within the housing cover in order to conduct heat from the individual chips to the housing cover. In this case, the covers have snap-action hooks which reach over the edges of the circuit board and clamp the covers onto the circuit board on both sides. In this design, there is the risk of impermissible heating of adjacent semiconductor devices which intrinsically generate a reduced power loss and are then impermissibly additionally heated by the heat distribution of the thermally conductive substance and the thermally conductive covers. Moreover, there is also the disadvantage of an increased material outlay, which increases manufacturing costs.
A further known heat sink design includes providing individual semiconductor devices directly with a heat sink, where the heat sink is adhesively bonded onto the rear side of the housing by means of a thermally conductive adhesive. Solutions of this type have the disadvantage that, in mechanical shock tests and in vibration tests and also in the case of other manual influences, an impermissibly high mechanical stress may be exerted on the devices to be cooled by virtue of the heat sink bonded on adhesively, which may result in damage to the semiconductor device.